On average, space heating and cooling accounts for 50-70% of the energy use of a US home (Al-Homoud, 2005). This percentage could be higher in other parts of the world with harsher climatic conditions and less energy efficient buildings, for example in the Gulf region. Thermal insulators, as part of building materials and some industrial hardware, are therefore steadily gaining importance as a means of saving energy.
Thermal insulation serves in reducing energy losses during the whole year by maximizing the efficiency of both cooling and heating systems. Savings in energy consumption will reduce both costs and carbon emissions.
Thermal insulation materials available in the Gulf region are relatively expensive and until now are infrequently used by local contractors. In addition, the typical insulation materials; polyurethane, polystyrene, and mineral wool (Cabeza et al., 2010) suffer from poor mechanical properties, which limit their application in the construction process. Consequently, there is a necessity to develop a thermal insulation material that possesses excellent mechanical and physical properties as far as energy saving, water resistance, ease of handling and machining are concerned. At the same time, it should be relatively cheap so that it may be used extensively.
Many presently available insulating materials are made of polymer materials, fillers, and other additives, i.e. they are composite materials. Polymers are generally known to be good insulating materials due to their stable physical and chemical properties. Mechanical properties, however, can be further improved or modified with the addition of fillers as demonstrated by the increase in the strength of the composite (Liu et al., 2008). Many kinds of clay minerals such as bentonite, kaolin, talc, mica, etc. have been used as inorganic fillers for the conventional polymer composites to reduce the cost or to give them special properties such as modulus, hardness, thermal stability, electrical insulation, thickening, opacity and brightness (Ismail et al., 1999; Abu-Jdayil et al., 2002; Lee and Lee, 2004; Al-Malah and Abu-Jdayil, 2007; Abu-Jdayil and Al-Malah, 2008).
Mixtures of fly ash, lime and phophogypsum known as fly ash-lime-phosphogypsum cements were used in the application and manufacturing of building materials such as bricks and structural concretes (Singh and Garg, 1995; Kumar, 2003). Goncalves and Bergmann (2007) have utilized the rice husk ashes to produce thermal insulators. They found that the thermal conductivity of the rice husk ash insulators is low (between 0.15 and 0.28 watts per meter kelvin difference (W/mK)), but higher than a commercial thermal insulator made from diatomaceous silica, used as reference. Agoudjil et al. (2011) reported the results of an experimental investigation on the thermophysical, chemical and dielectric properties of three varieties of date palm wood to be used in thermal insulation for buildings. Polyurethane/wood-based composites were synthesized with wood waste from furniture companies and polyols obtained from chemically recycled poly(ethylene terephthalate) (PET) and commercial polyols (Fornasieri et al., 2011). Although the Young's modulus and tensile strength of the composites have been improved, no significant improvement in the thermal stability of the composites was observed. Recently, Qin et al. (2011) have investigated the mechanical and thermal properties of poly (lactic acid) composites with rice straw fiber modified by poly (butyl acrylate) to be used in different applications. However, values for thermal conductivity were not reported. Mourad et al. (2009, 2010, 2013) have studied the mechanical, thermal and chemical properties of different polymer composite materials and very recently they (2013) have developed a novel technique to produce rice straw-based fiberboards and characterized their physico mechanical properties.
Date pits are readily available in a number of countries. Date pits have typically been seen as waste product from the preparation of dates and are usually discarded. In the United States, pulverised ground date pits are being used on a small scale, on dirt roads as a type of road base gravel. In the Middle East, it is sometimes used in animal feed (Banat et al., 2003). Several investigators have used date-pits to adsorb dye (Banat et al., 2003), aluminum (Al-Muhtaseb et al., 2008), heavy metals (Al-Ghouti et al., 2010), and phenol (El-Naas et al., 2010).